Hormetic response and transcriptome profiling reveal the mechanism underlying metabolic and cuticular resistance to host-specific terpenoid defenses in an emerging insect pest, Pagiophloeus tsushimanus (coleoptera: curculionidae)

ABSTRACT: The resistance mechanisms evolved by insects to overcome host-plant allelochemicals is a key consideration in pest management. Camphor oil (EO) and its main component (i.e D-camphor) form a specific terpenoid-defensive system in camphor trees, Cinnamomum camphora. However, an emerging insect pest, Pagiophloeus tsushimanus has recently caused serious damage to this intractable plant species, which is largely elusive. Here, we used feeding bioassays and RNA-seq to investigate the mechanism underlying the resistance of the beetle to host-specific terpenoid defenses. Firstly, a hormetic response in both larval weight and developmental time was observed in terpenoid-feeding individuals, which is a highly generalized dose-response phenomenon in toxicology whereas occurs infrequently in the context of insect-plant interactions. Then, comparative transcriptome analysis between terpenoid-feeding and control groups indicated that both CYP450s-mediated metabolic resistance and CPs-mediated cuticular resistance were jointly employed to cope with terpenoid-induced stress. In addition, a small portion of genes involved in glucose transport pathway were up-regulated at the low D-camphor dose, suggesting an extra intake of glucose used for larval growth may contribute to a hormetic response. These findings probably implied that the dual terpenoid-resistance mechanisms existing in this specialist is an essential precondition for hormetic response in larval growth, ultimately contributing to successfully colonize host camphor trees with impunity. Overall, our study will open new avenues for understanding the insect-plant coevolutionary adaptation and developing durable pest control strategies.

ORGANISM(S): Pagiophloeus tsushimanus

PROVIDER: GSE182420 | GEO | 2021/08/21

REPOSITORIES: GEO